Uranium Workshops Dismantling and Criticality Control

Within the CEA at Cadarache Research Center located in southern France, the ATUE, standing for Ateliers de Traitement de l’Uranium Enrichi (Enriched Uranium Treatment Workshops), is a nuclear facility started in 1965 and shut down in 1995. Various chemical processes were in operation in the ATUE in order to product enriched uranium oxide intended for fast breeders and naval propulsion reactors. According to the mass of fissile material, the most contaminated process equipment has already been dismantled under criticality risk management procedures. Cleanup of the building and dismantling of the remaining equipment, such as ventilation and electricity network, are now in progress without any constraint regarding criticality, thanks to in-situ measurement and calculations. Criticality management and how we finally proved the risk was over, as well as the strategy under French rules for final decommissioning of the facility leading to “brown field” will be presented.